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The flowers of Peperomia (Piperaceae) are simple, minute, and unique structures within the angiosperms consisting of a rounded bract, two stamens and an ovary, but generally lack taxonomic value at species level. Because of this, morphological characters of vegetative parts have been mainly used for species level taxonomy. There is a need to supplement these vegetative characters with anatomical characters. We selected 17 native Thai species representatives of South East Asian Peperomia to investigate the utility of vegetative anatomical characters for species delimitation, taxon identification, and classification. Stem, petiole, and leaf anatomical characters were studied using standard microscopic techniques. The anatomical characters demonstrated high diversity and supported species identification. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) culstering, Principal Coordinates analysis (PCoA), and Principal Component Anaysis (PCA) were used to investigate patterns in the multivariate anatomical data and identify groupings of value to species classification. Four broad groupings were retrieved and some subgroupings identified. The most important characters that differentiated the species in the multivariate analysis included stem shape (roundness and ridges), petiole indumentum and trichome type, vascular bundle pattern and number, stem pith cavity, mucilage canals, and stem cortex sclerenchyma. These data were further used to prepare anatomical descriptions at generic and species levels and to provide a key to species. [ABSTRACT FROM AUTHOR]

Disporopsis longifolia Craib is an Asian medicinal plant belonging to the Asparagaceae family. The plants are well known for their steroidal saponins and phenolic compounds and are traditionally used as tonics for back pain, bellyache, cough, diabetes, asthma, pneumonia and rheumatism. However, they are challenging to identify to species level using morphology. This raises a serious concern for their medicinal applications where botanical quality control is essential. The most appropriate morphological, anatomical and pollen characters for species diagnosis were therefore determined. Synonyms were identified and lectotypification provided. The morphological characters were described from 76 fresh and dried specimens to include a broad range of materials from differing habitats and locations. Paraffin and peeling methods were applied for anatomical studies of leaves and stems and a modified acetolysis method was undertaken for pollen morphology. This paper compares the new character data to published data from other species in the genus, namely D. aspersa, D. fuscopicta, D. jinfushanensis, D. pernyi and D. undulata. This is the first report of such anatomical and pollen morphology characters for D. longifolia. The results provide accurate morphological, anatomical and palynological characters for quality control and are best applied in combination with each other. [ABSTRACT FROM AUTHOR]